Longman Dictionary of Contemporary English
Wikipedia
A private secretary (PS) is a civil servant in a governmental department or ministry, responsible to a secretary of state or minister.
A private secretary is normally of middle management level; however, as the key official responsible for disseminating the decision of ministers and indeed as their gatekeeper, his or her role is of considerably greater significance than this grade or level suggests. Depending on what level of politician the official works for they will be assisted by one or more assistants and or deputy secretaries, or even head a whole office in which those may be section chiefs.
Private Secretary (also known as Susie) is an American sitcom that aired from February 1, 1953 to September 10, 1957 on CBS, alternating with The Jack Benny Program on Sundays at 7:30pm EST. The series stars Ann Sothern as Susan Camille "Susie" MacNamara, devoted secretary to handsome talent agent Peter Sands, played by Don Porter.
Usage examples of "private secretary".
She took the short walk to her husband's office and went through the door without even looking at Ed's private secretary.
In addition to Francis Dana, John Thaxter would go as Adams's own private secretary and tutor for the boys.
His diary entry droned on for twenty minutes, his trained memory recounting every substantive part of his exchange with Zhang, who was doubtless doing the same with his own private secretary right at this moment--- unless Zhang had succumbed to the Western practice of using a tape machine, which would not have surprised Fang.
He is expected back at the White House tomorrow, and Grant is expected to keep him on as private secretary.